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Steelmaking 2017 Vol.33 Please wait a minute... For Selected: Download Citations EndNote Ris BibTeX Toggle Thumbnails Select   Technological progress of BOF steelmaking in period of development mode transition Steelmaking    Accepted: 01 January 1900 Select Melting slagging mechanism and application of lime and limestone in BOF steelmaking Steelmaking    Accepted: 01 January 1900 Select Study on theoretical substitution ratio of lime stone with CaO based on thermal equilibrium in BOF steelmaking process Steelmaking    Accepted: 01 January 1900 Select Influence of converter slag on decomposition temperature and activity energy of limestone Steelmaking    Accepted: 01 January 1900 Select The explosion behavior of limestone particles during calcination at steelmaking temperature Steelmaking    Accepted: 01 January 1900 Select Silicon volatilization and control during slagging by limestone in BOF Steelmaking    Accepted: 01 January 1900 Select Study on the physico-chemical properties and microstructure of lime rapidly calcined at high temperature Steelmaking    Accepted: 01 January 1900 Select The effect of CO2 oxidation on hot metal arising from CaCO3 decomposition in BOF Steelmaking    Accepted: 01 January 1900 Select Kinetics study on decomposition reaction of limestone under ultra-high temperature Steelmaking    Accepted: 01 January 1900 Select Study and practice through dispersed in-situ phase induced by composite of sludge and dust ball explosive reaction Steelmaking    Accepted: 01 January 1900 Select Inducing mechanism of IGF for the casting structure of Ti-Mg shipbuilding steel Steelmaking    Accepted: 01 January 1900 Select Investigation on relationship between nozzle clogging and large inclusions in bearing steel bars Steelmaking    Accepted: 01 January 1900 Select Current state and prospect of technologies for removing inclusion by bubbles Steelmaking    2017, 33 (2): 1-9.   Abstract （104）            Knowledge map    Save Using bubbles to remove inclusions in steel is now becoming one of the important means of refining. The mechanism on inclusion removal by bubbles shows that inclusion floating through adhering by bubbles and involving in bubble wake are two main means of inclusion removal by bubbles. It has become a consensus that tiny bubbles have excellent effect on inclusion removal. In the present study, different inclusion removal methods by using bubbles and their prospect have been analyzed and compared, such as the argon blowing, argon injecting into shroud, fine and uniform heterophases in the molten steel, air curtain in the tundish, pressure elevating and reducing method, ultrasonic cavitation method, nitrogen absorbing and releasing method, inclusions removal by fine hydrogen bubbles method etc. The results show that tiny bubbles generated in steel on inclusions removal have better effect than the big bubbles. Nowadays, using dispersion tiny bubbles to remove inclusions in steel is paid more attention by the metallurgists. Some of the new inclusion removal technologies have been developed and are tending to be matured. Related Articles | Metrics Select Impact of electromagnetic stirring on the stainless steel melting process in EAF Steelmaking    2017, 33 (2): 10-14.   Abstract （119）            Knowledge map    Save Electromagnetic stirrer installed underneath the furnace bottom creates a whole bath mixing effect thus accelerates the homogenization of the temperature and chemical composition of the steel. The effect of electromagnetic stirring on the EAF process for stainless steel melting had been studied in a 90 t furnace in Outokumpu Stainless AB in Sweden. The hot test results showed that ArcSave accelerated the scrap and ferrochromium melting and gave a better accuracy in tapping weight control. Bath temperature was more homogeneous and tapping temperature was controlled more correctly and this would smooth the AOD operations. The decrease of surface superheat temperature and efficient heat transfer under stirring would reduce the heat losses to the furnace wall and roof and thereby reduced the electricity and electrode consumption. The total energy saving could be reached to 3 %－4 %. The slag reduction was also enhanced by stirring which resulted in high alloy yield and lower FeSi consumption. Short taptotap time and consistent furnace operation also enabled an increase in productivity of approx 6 %－8 %. Electromagnetic stirring is a reliable and efficient solution for improving the stainless steel melting process. Related Articles | Metrics Select Optimization of LF refining slag of 20CrMnTi gear steel Steelmaking    2017, 33 (2): 15-19.   Abstract （95）            Knowledge map    Save Aiming at the problems such as high total oxygen control and poor control of inclusion in the production of 20CrMnTi gear steel, the effects of bacisity of refining slag, ratio of w(CaO)/w(Al2O3), and MI index on the adsorptioncapacity of Al2O3 inclusions were mainly discussed through the calculation result of FactSage thermodynamics software in the paper. The results show that the main composition of refining slag suitable for the production of gear steel (20CrMnTi) in the steel plant is as below: w(CaO)=50 %-55 %，w(Al2O3)=22 %-26 %，w(SiO2)=10 %-12 %，w(MgO)=5 %-7 %. And applying this refining slag in industrial tests, the total oxygen mass fraction decreased from 17×10-6 to 14×10-6. Besides, the average size of inclusions in billets also significantly decreased from 2.0 μm to 1.4 μm, and most of the observed inclusions change within the 1 500 ℃ liquidus, inclusion modification effect is good. Related Articles | Metrics Cited: Baidu(1) Select Effect analysis of different secondary refining process on low-carbon aluminium killed steel Steelmaking    2017, 33 (2): 20-.   Abstract （88）            Knowledge map    Save In order to reasonably choose second refining process of low carbon aluminum killed steel, meet the requirements of clean, efficient, low cost and stable mass production in modern steel plant, the five different second refining processes of LF with calcium treatment, CAS, LF without calcium treatment，RH ordinary treatment, RH light treatment were compared and analysised.  Results showed that RH light treatment technology was more suitable for lowcarbon aluminium killed steel in narrow composition control of carbon content, and the lowest cost was 33.17 yuan/t. The purity of molten steel by RH ordinary treatment process was the best，the total oxygen mass fraction of liquid steel was 16×10-6 in tunsish, the inclusion amount was 11.2/mm2 at the end of refining. RH light treatment process should be preferred, followed by RH ordinary treatment or CAS refining process. Ladle furnace equipment can not use calcium treatment process, but LF refining + calcium treatment has more advantages for steel plant of that need desulfuring and continuous casting nozzle blocking. Related Articles | Metrics Select Analysis of thermal field of the new type of vacuum vessel of integrated snorkel tube Steelmaking    2017, 33 (2): 28-32.   Abstract （92）            Knowledge map    Save The variation of temperature field of the new type of vacuum vessel of snorkel tube during a refining process period was studied by field measurement method and finite element method technology，and compared with the vacuum vessel of separated snorkel tube. The results showed that, the vacuum vessel of integrated snorkel tube FEM results were in good agreement with the measured data. During a refining process period, the temperature of upper portion of the vacuum vessel trended to steady state. The temperature of lower portion of the vacuum vessel increased first and then decreased. The temperature was the highest at the end of the vacuum refining process, and was the lowest at the end of online standby state. The vacuum vessel of integrated snorkel tube could meet the thermal condition at the end of online standby state, and could be used without the online baking between the two refining process. The temperature field of vacuum vessel of integrated snorkel tube was consistent with the separated snorkel tube at the end of the refining process, which proved the feasibility of the new type of the integrated snorkel tube. Related Articles | Metrics Select Energy conservation for RH ladle lifting hydraulic system Steelmaking    2017, 33 (2): 33-37.   Abstract （83）            Knowledge map    Save Taking 300 t RH project for example, the hydraulic composition and pumpcontrol velocity regulation closed loop system were introduced. Focusing on energy conservation, loadsensing pump, accumulator energy recovery and independent control of actuator were designed. The energy conservation for different schemes were researched and analyzed. The project application result proved that 3.84×107 kJ per year energy were saved and 39 % energy were reduced compared to common stable pressure pump system for continuous production, while energy conversation effect applying stable variable pump system was large for intermittent production. For the heat value and failure rate, loadsensing pump system in the second stage project greatly welcomed by the client were obviously reduced compared to stable variable pump system in the first stage project. Related Articles | Metrics Select Investigation and development of a new type ladle with vacuum wall Steelmaking    2017, 33 (2): 38-42.   Abstract （97）            Knowledge map    Save To reduce the thermal loss of molten steel which cannot be reduced from the refractory materials and surfaces of molten steel during the production, a new technique that radiationproof steel plates are welded on the exterior walls of conventional ladle and its lid for forming a cavity shell, was proposed. Based on the thermal insulation principle of vacuum, the relationship of vacuum pressure and temperature drop, combined thermal transfer and the optimum pressure inside chamber were investigated. The results showed that，newtype ladle is therefore better in thermal insulation than conventional ladle.  When the absolute pressure inside the chamber of the ladle and its lid is set to 50 Pa, the temperature drop of molten steel is a mere 8 K, while the steel is held with the combination of the conventional ladle and its lid, the temperature drop reaches 35 K. The chamber at 50－100 Pa will obtain a better effect in the actual production. Related Articles | Metrics Select Optimization of casting speed for tail billet during the end of continuous casting Steelmaking    2017, 33 (2): 43-49.   Abstract （107）            Knowledge map    Save A new casting speed reduction technology of tundish tail billet has been developed in base of final cast close up operation in order to solve the problem of high waste rate of the factory in ultraheavy plate continuous casting production, which because superficial quality unqualified of tail billet peeling treatment. The numerical simulation of the influence of the new technology on the flow field in the tundish was carried out which applied computational fluid dynamics software FLUENT. The final scheme of tail billet casting speed reduction has been established: residual casting of molten steel is 10 t, and casting speed reduction operation should be started from the speed of 0.9 m/min, the speed reduction of 0.05 m/min each time, the duration time on each speed is:2-5-10-5-10-5-10-5-10-5-10-5-10-10 s. The close up operation should be started in the speed of 0.2 m/min and the duration time is 350 s. The optimization of tundish tail billet casting speed reduction scheme can save the tail billet casting speed reduction time 243 s, reduce casting tail billet length 1.1 m（4.62 t）, decrease tail billet 2.62 t(residual casting of molten steel increased 2 t). After the optimization scheme of tail billet casting speed has been adopted, waste products occurrence rate of ultraheavy continuous casting tail billet in the factory dropped to 18.9 % from 30 %. Related Articles | Metrics Select Investigation on technology of non-metallic inclusion control for high grade special steels of important uses Steelmaking    2017, 33 (2): 50-56.   Abstract （154）            Knowledge map    Save Results of investigations on non-metallic inclusion control for high speed train axle steel and saw wire steel used for silicon wafer cutting are described in this article: (1) By means of further strengthening the RH vaccum refining, strictly control of the reoxidation and forming liquid inclusions which are not easy to aggregate to largesized inclusions, the number of the largesized inclusions in high speed train axle steel which contains 0.000 45 %－0.000 6 % T.O has been considerably reduced. (2) For the saw wire steel, by means of decreasing the amount of CaO-SiO2-Al2O3 system inclusions, forming the MnO-SiO2-Al2O3/SiO2 dual-phase inclusions and strictly control of exogenous inclusions, the broken-resistance property of the steel wire in cold drawing fabrication has been remarkablly enhanced. (3) With the developed technologies, the wheel sets produced by Ma Steel Co. has been applied to the high speed trains on ShanghaiKunming line. The nonbroken length of the saw wires produced by Xingtai Iron and Steel Co. has been increased to more than 10 km, which has reached the world top saw steel product property level. Related Articles | Metrics Select Process optimization of X52 sour service pipeline steel Steelmaking    2017, 33 (2): 57-62.   Abstract （129）            Knowledge map    Save There are some issues in the production of sour service pipeline steel, which includes being hard to control carbon, sulfur, phosphorous; high ferrous charge consumption. The root cause was analyzed by thermodynamic calculation combined with production data. The countermeasure was put forward from EAF melting, alloying mechanism, prerefining at EAF tapping, LF refining slag and raw material addition mechanism. After the optimized process was applied, at EAF tapping rephosphorization fraction decreased from 32.3×10-6 to 6.6×10-6，carburization fraction decreased from 0.038 % to 0.011 %，desulphurization ratio increased from 27.0 % to 44.1 %; desulphurization ratio in the LF process increased from 84.1 % to 89.5 %, ferrous charge consumption decreased from 1 130 kg/t to 1 070 kg/t, lime consumption decreased from 85.4 kg/t to 33.1 kg/t, aluminum consumption decreased from 2.6 kg/t to 2.1 kg/t, oxygen consumption decreased from 35.1 m3/t to 24.4 m3/t, electricity consumption decreased from 445.8 kWh/t to 422.1 kWh/t, and hence the production cost decreased significantly; the cleanness of liquid steel improved dramatically at LF end, the area ratio of micro inclusion decreased by 29.3 %. Related Articles | Metrics Select Effect of Al2O3and MgO on the viscosity and structure of Cr-containing slags Steelmaking    2017, 33 (2): 63-68.   Abstract （109）            Knowledge map    Save In order to obtain the good liquidity of slag and optimize the slagmetal separation in ferrochrome process, the investigation of the effect of Al2O3 and MgO on the viscosity of Cr-containing slag has great theoretical value. From the viewpoint of microscopic structure, the effect of Al2O3 and MgO on the viscosity has been investigated by Raman spectroscopy. Experimental results indicate that the viscosity of Cr-containing slag increases with the increasing Cr2O3 and Al2O3 content，whereas decreases with increasing MgO at the Newtonian flow region. Combined with Raman spectrum analysis results, the amounts of more polymerised units Q2Si and Q3Si  increase with the increasing of Al2O3  content, and the less polymerised units Q1Si and Q0Si decreases, the number of nonbridging oxygens per Si atom (NBO/Si) participating in the formation of network structure decreases, while the degree of polymerization is greater. Along with the increase of the content of MgO, the more polymerised units Q3Si transform into the less polymerised Q1Si and Q0Si, the NBO/Si ratio increases, and the degree of polymerization gets lower, variation tendency of slag viscosity is consistent with polymerization degree, therefore, through the analysis of contents on the degree of polymerization can directly reflect the variation of viscosity. Related Articles | Metrics Select The causes and improvement measures of delaminate defects on P91 heat-resistant steel Steelmaking    2017, 33 (2): 69-.   Abstract （90）            Knowledge map    Save In order to improve the quality of P91 steel products, causes of delaminate defects on P91 steel were analyzed by scanning electron microscopy (SEM) and ASPEX. The results showed that magnesiaalumina spinel and calcium aluminate of steelmaking process led to stress concentration in the machining process. Inclusion gathering place was easy to form crack and delamination. The low index of inclusion level and total oxygen content reflected problems upon steel cleanliness. By means of optimizing refining slag composition (w（CaO）=55 %－60 %，w（SiO2）=10 %－15 %，w（Al2O3）=18 %－23 %), using nitriding technology and high quality magnesia carbon brick to improve anti-erosion on 10 furnaces trial-manufacture, the inclusion level was stably controlled below 1.0 grade and w（T.O） was reduced from 21.04×10-6 to 16.73×10-6. The delaminate defects reduced and the steel tube product yield increased by 15 %. Related Articles | Metrics Select Study on cleanliness of IF steel first heat of a sequence Steelmaking    2017, 33 (2): 74-78.   Abstract （177）            Knowledge map    Save System of a factory for the open casting heats IF steel slab cleanliness variation on the slab level provide the basis for rational judgment, the use of oxygen and nitrogen analysis, quantitative metallographic examination and other tests detect large inclusions of a steel open casting furnace second IF steel slab cleanliness research. The results showed that, at 4 m distance from the dummy bar head in slab w(T.O)=35.3 ×10-6,w(N)=48.7× 10-6, microscopic inclusions content was 8.5/mm2, steel secondary oxidation serious, which contains trace elements La, microscopic inclusions proportion of Ce, respectively 33 %and 55 % by the ladle slag and tundish slag greater impact. At 16 m distance from dummy bar head, w(T.O)=18.7×10-6, slab has greatly improved cleanliness. With casting cleanliness is more gentle upturn, 28 m away from the dummy bar head , w(T.O)decreased to 16.3×10-6, the cleanliness of the slab continuous casting furnace 2, 3 stove heats consistent with normal. Related Articles | Metrics Select Progress and trends of research on mold fluxes used in continuous casting Steelmaking    Accepted: 01 January 1900 Select Development and prospect of mold fluxes for the casting of advanced high strength steels Steelmaking    Accepted: 01 January 1900 Select Shear thinning property analysis of Non-Newtonian fluid mold flux Steelmaking    Accepted: 01 January 1900 Select Investigation on crystallization kinetics of mold fluxes based CaO-SiO2-Al2O3 by using the differential scanning calorimetry Steelmaking    Accepted: 01 January 1900 Select Application of the confocal laser scanning microscope method in study on wettability of solid steel by molten slags Steelmaking    Accepted: 01 January 1900 Select Study on the crystallization characteristics of continuous casting mold flux under high frequency magnetic field Steelmaking    Accepted: 01 January 1900 Select Investigation on development of low-Li2O mold fluxes used for high aluminum steel Steelmaking    Accepted: 01 January 1900 Select Analysis of longitudinal cracks and optimization of mold flux for high strength automotive steel slab Steelmaking    Accepted: 01 January 1900 Select Mineralogical structure and formation mechanism of flux film for peritectic steel and thin slab casting Steelmaking    Accepted: 01 January 1900 Select Analysis the surface peeling of cold-rolled and optimization slag of low carbon aluminum killed steel Steelmaking    Accepted: 01 January 1900 Select Research of model for thermal insulation performance of mold flux Steelmaking    Accepted: 01 January 1900 Select Investigation on the surface crack of TRIP590 hot rolled strip and the optimization of mold flux Steelmaking    Accepted: 01 January 1900 Select New tendency and process innovation for special steels Steelmaking    2017, 33 (4): 1-11.   Abstract （149）            Knowledge map    Save From the summary on domestic and international development in special steels, it can be seen that the focal point for quality improvement has been transferred from cleansteel refining technology to largesizeinclusion controltechnology, especially to the sulfide control. The maximum size of inclusions affects the fatigue property of special steels obviously, and when the total oxygen content w(T.O)≤5×10-6，the influence of sulfide is most serious. The large size inclusions are mainly originated from MgO-Al2O3 and CaO-Al2O3  by slagmelt reaction, as well as from CaO-SiO2-Al2O3 by involved slag. To control the large-size inclusions, the following process technologies must be improve: lower down the operating load of refining process, optimize deoxidation process, control slag-involving strictly, and promote inclusions floating upward during continuous casting. Related Articles | Metrics Select The research on deep desulphurization process of bearing steel during LF refining Steelmaking    2017, 33 (4): 12-18.   Abstract （132）            Knowledge map    Save Through analyzing the industrial data and discussing the factors affecting the slag composition, basicity，CS and w(Ca)/w(Al), the corresponding optimization measures of the smelting process was proposed from two aspects of desulfurization thermodynamics and kinetics in order to further reduce the sulfur content in bearing steel. The results showed that controlling w(SiO2)≤5 %, refining slag basicity R≥10, w(FeO+MnO)≤0.5 % and w(CaO)/w(Al2O3)=1.6－1.7, desulphurization effect was the best, desulphurization rate of bearing steel could be reached 94 %, the mass fraction of sulfur in steel was no more than 20×10-6. Related Articles | Metrics Select Research on continuous casting grades transition process by hydraulic model of CSP 45 t single strand tundish Steelmaking    2017, 33 (4): 19-22.   Abstract （99）            Knowledge map    Save Aimed at the problem of complicated production organization and high cost of continuous casting, which is due to multiproduct and small batch of high performance steels in CSP plant of Wuhan Iron and Steel Co.,Ltd. Length of the transition slab during the CSP casting was investigated by hydraulic modelling and pilot trials. The used water model was in a proportion of 1∶2 to simulate the industrial tundish with a capacity of 45 t. During the simulation, the conditions satisfied the Froude number similarity principle. Important factors which affect the flow and mixing of liquid steel were taken into account, including the casting speed and the weight of residual molten steel in tundish. As a result, concentration curves along the casting direction were analyzed and obtained. It was found that the minimum length of the intermixing slab was about 22.4m when the residual molten steel and casting speed were about 10 t and 4.5m/min, respectively. Hereafter, industrial trials were carried out, which agreed with the obtained results in the cold model simulation. After application, the problem of complicated production organization, which is due to multiproduct and small batch of high, was be relieved. Productivity of high performance steels was increased and the cost was effectively reduced in CSP plant. Related Articles | Metrics page Page 1 of 2 Total 75 records First page Prev page Next page Last page